[PATCH 4.14 168/193] powerpc/64s/hash: Fix 512T hint detection to use >= 128T

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Michael Ellerman <mpe@xxxxxxxxxxxxxx>

commit 7ece370996b694ae263025e056ad785afc1be5ab upstream.

Currently userspace is able to request mmap() search between 128T-512T
by specifying a hint address that is greater than 128T. But that means
a hint of 128T exactly will return an address below 128T, which is
confusing and wrong.

So fix the logic to check the hint is greater than *or equal* to 128T.

Fixes: f4ea6dcb08ea ("powerpc/mm: Enable mappings above 128TB")
Suggested-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Suggested-by: Nicholas Piggin <npiggin@xxxxxxxxx>
[mpe: Split out of Nick's bigger patch]
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/powerpc/mm/slice.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/powerpc/mm/slice.c
+++ b/arch/powerpc/mm/slice.c
@@ -419,7 +419,7 @@ unsigned long slice_get_unmapped_area(un
 	/*
 	 * Check if we need to expland slice area.
 	 */
-	if (unlikely(addr > mm->context.addr_limit &&
+	if (unlikely(addr >= mm->context.addr_limit &&
 		     mm->context.addr_limit != TASK_SIZE)) {
 		mm->context.addr_limit = TASK_SIZE;
 		on_each_cpu(slice_flush_segments, mm, 1);
@@ -427,7 +427,7 @@ unsigned long slice_get_unmapped_area(un
 	/*
 	 * This mmap request can allocate upt to 512TB
 	 */
-	if (addr > DEFAULT_MAP_WINDOW)
+	if (addr >= DEFAULT_MAP_WINDOW)
 		high_limit = mm->context.addr_limit;
 	else
 		high_limit = DEFAULT_MAP_WINDOW;